[bpf-next,v3,0/4] bpf: verifier: use target program's type for access verifications

This patch series adds changes in verifier to make decisions such as granting
of read / write access or enforcement of return code status based on
the program type of the target program while using dynamic program
extension (of type BPF_PROG_TYPE_EXT).

The BPF_PROG_TYPE_EXT type can be used to extend types such as XDP, SKB
and others. Since the BPF_PROG_TYPE_EXT program type on itself is just a
placeholder for those, we need this extended check for those extended
programs to actually work with proper access, while using this option.

Patch #1 includes changes in the verifier.
Patch #2 adds selftests to verify write access on a packet for a valid 
extension program type
Patch #3 adds selftests to verify proper check for the return code
Patch #4 adds selftests to ensure access permissions and restrictions 
for some map types such sockmap.

Changelogs:
  v2 -> v3:
    * more comprehensive resolution of the program type in the verifier
      based on the target program (and not just for the packet access)
    * selftests for checking return code and map access
    * Also moved this patch to 'bpf-next' from 'bpf' tree
  v1 -> v2:
    * extraction of the logic to resolve prog type into a separate method
    * selftests to check for packet access for a valid freplace prog

Udip Pant (4):
  bpf: verifier: use target program's type for access verifications
  selftests/bpf: add test for freplace program with write access
  selftests/bpf: test for checking return code for the extended prog
  selftests/bpf: test for map update access from within EXT programs

 kernel/bpf/verifier.c                         | 32 ++++++---
 .../selftests/bpf/prog_tests/fexit_bpf2bpf.c  | 68 +++++++++++++++++++
 .../selftests/bpf/progs/fexit_bpf2bpf.c       | 27 ++++++++
 .../bpf/progs/freplace_attach_probe.c         | 40 +++++++++++
 .../bpf/progs/freplace_cls_redirect.c         | 34 ++++++++++
 .../bpf/progs/freplace_connect_v4_prog.c      | 19 ++++++
 .../selftests/bpf/progs/test_pkt_access.c     | 20 ++++++
 7 files changed, 229 insertions(+), 11 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/freplace_attach_probe.c
 create mode 100644 tools/testing/selftests/bpf/progs/freplace_cls_redirect.c
 create mode 100644 tools/testing/selftests/bpf/progs/freplace_connect_v4_prog.c

On 8/25/20 4:19 PM, Udip Pant wrote:
> This patch series adds changes in verifier to make decisions such as granting
> of read / write access or enforcement of return code status based on
> the program type of the target program while using dynamic program
> extension (of type BPF_PROG_TYPE_EXT).
> 
> The BPF_PROG_TYPE_EXT type can be used to extend types such as XDP, SKB
> and others. Since the BPF_PROG_TYPE_EXT program type on itself is just a
> placeholder for those, we need this extended check for those extended
> programs to actually work with proper access, while using this option.
> 
> Patch #1 includes changes in the verifier.
> Patch #2 adds selftests to verify write access on a packet for a valid
> extension program type
> Patch #3 adds selftests to verify proper check for the return code
> Patch #4 adds selftests to ensure access permissions and restrictions
> for some map types such sockmap.
> 
> Changelogs:
>    v2 -> v3:
>      * more comprehensive resolution of the program type in the verifier
>        based on the target program (and not just for the packet access)
>      * selftests for checking return code and map access
>      * Also moved this patch to 'bpf-next' from 'bpf' tree
>    v1 -> v2:
>      * extraction of the logic to resolve prog type into a separate method
>      * selftests to check for packet access for a valid freplace prog
> 
> Udip Pant (4):
>    bpf: verifier: use target program's type for access verifications
>    selftests/bpf: add test for freplace program with write access
>    selftests/bpf: test for checking return code for the extended prog
>    selftests/bpf: test for map update access from within EXT programs
> 
>   kernel/bpf/verifier.c                         | 32 ++++++---
>   .../selftests/bpf/prog_tests/fexit_bpf2bpf.c  | 68 +++++++++++++++++++
>   .../selftests/bpf/progs/fexit_bpf2bpf.c       | 27 ++++++++
>   .../bpf/progs/freplace_attach_probe.c         | 40 +++++++++++
>   .../bpf/progs/freplace_cls_redirect.c         | 34 ++++++++++
>   .../bpf/progs/freplace_connect_v4_prog.c      | 19 ++++++
>   .../selftests/bpf/progs/test_pkt_access.c     | 20 ++++++
>   7 files changed, 229 insertions(+), 11 deletions(-)
>   create mode 100644 tools/testing/selftests/bpf/progs/freplace_attach_probe.c
>   create mode 100644 tools/testing/selftests/bpf/progs/freplace_cls_redirect.c
>   create mode 100644 tools/testing/selftests/bpf/progs/freplace_connect_v4_prog.c

Thanks. LGTM. Ack for the whole series.
Acked-by: Yonghong Song <yhs@fb.com>

Udip Pant <udippant@fb.com> writes:

> This patch series adds changes in verifier to make decisions such as granting
> of read / write access or enforcement of return code status based on
> the program type of the target program while using dynamic program
> extension (of type BPF_PROG_TYPE_EXT).
>
> The BPF_PROG_TYPE_EXT type can be used to extend types such as XDP, SKB
> and others. Since the BPF_PROG_TYPE_EXT program type on itself is just a
> placeholder for those, we need this extended check for those extended
> programs to actually work with proper access, while using this option.
>
> Patch #1 includes changes in the verifier.
> Patch #2 adds selftests to verify write access on a packet for a valid 
> extension program type
> Patch #3 adds selftests to verify proper check for the return code
> Patch #4 adds selftests to ensure access permissions and restrictions 
> for some map types such sockmap.

Thanks for fixing this!

For the series:
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>

On Tue, Aug 25, 2020 at 04:19:59PM -0700, Udip Pant wrote:
> This patch series adds changes in verifier to make decisions such as granting
> of read / write access or enforcement of return code status based on
> the program type of the target program while using dynamic program
> extension (of type BPF_PROG_TYPE_EXT).
> 
> The BPF_PROG_TYPE_EXT type can be used to extend types such as XDP, SKB
> and others. Since the BPF_PROG_TYPE_EXT program type on itself is just a
> placeholder for those, we need this extended check for those extended
> programs to actually work with proper access, while using this option.
> 
> Patch #1 includes changes in the verifier.
> Patch #2 adds selftests to verify write access on a packet for a valid 
> extension program type
> Patch #3 adds selftests to verify proper check for the return code
> Patch #4 adds selftests to ensure access permissions and restrictions 
> for some map types such sockmap.
> 
> Changelogs:
>   v2 -> v3:
>     * more comprehensive resolution of the program type in the verifier
>       based on the target program (and not just for the packet access)
>     * selftests for checking return code and map access
>     * Also moved this patch to 'bpf-next' from 'bpf' tree

Applied. Thanks